The present invention relates generally to a textile fiber drafting system. More specifically, it relates to provision of novel method and apparatus of drafting fibers of sliver, roving or the like which uses at least two pairs of top and bottom rollers and are utilized in combination with a ring spinner or a spinning frame for producing fasciated yarn.
In drafting fibers of sliver, roving or the like by means of a roller drafting mechanism including a pair of back rollers and another pair of front rollers rotating at a higher peripheral speed than said pair of back rollers, it is known that, for the purpose of minimizing irregularity in draft, a control must be provided for those fibers which are too short to be held by either nip of said pairs of back and front rollers through the use of any sliver guide means, e.g., that which is known as the Casablancas type arrangement, designed to support and guide such free short fibers in the drafting zone. This known guide device, which comprises a pair of rubber aprons trained over the peripheral surfaces of the back rollers, respectively, and driven to move at an identical speed, is designed and arranged to hold the sliver softly therebetween and transfer the same toward the high-speed running front rollers. Though this guide device can provide very effective support for the free short fibers in the sliver, a fiber drafting operation which uses such aprons has posed various problems associated therewith. These problems include damage or even fraying of the aprons due to their buckling motion at an acute angle adjacent to the fast running front rollers, damage thereto due to abnormal friction caused by entanglement of lint or fiber pieces around the aprons, etc. In a high-speed drafting arrangement used in combination with a spinner for producing fasciated yarn, in particular, a continuous drafting operation using such aprons without stopping (for 24 hours of operation in a day) for about one month at a peripheral speed of 150 meters per minute of the faster running rollers, causes the aprons to be broken eventually, thus showing poor strength and durability of the aprons which renders them inadequate for practical application.